Copolymerization of o-aminophenol (o-AP) and p-aminophenol (p-AP) in aqueous sulfuric acid solution was electrochemically performed using cyclic voltammetry on gold electrode. Copolymerization was carried out at different feed concentrations of homo monomers. The obtained films were characterized with cyclic voltammetry, in situ resistivity measurements, in situ UV-Vis-spectroscopy, FT-IR spectroscopy, and scanning electron microscopy (SEM). Cyclic voltammetry study shows that the onset potentials for o-AP, p-AP and o-AP p-AP are located at the different values. The results from the electrochemical copolymerization of o-AP with p-AP demonstrate that the CVs of copolymers films growth are different from those of homopolymers, and are strongly affected by the amount of monomers. The in situ resistivity of copolymers measured from -0.20 V to 0.95 V vs. SCE decreased with increasing the [o-AP]/[p-AP] concentration ratio. In situ UV-visible and ex situ FT-IR spectra of homopolymers and copolymers results show intermediate spectroscopic behavior between homopolymers and copolymers. SEM micrographs of the samples show fundamental differences between the morphology of the homo- and copolymers. (C) 2014 The Electrochemical Society. All rights reserved.